The following image processing system has been known as an operation support system for a vehicle. As illustrated in FIG. 1, a plurality of camera modules CA1 to CA4 images, at a fixed cycle, different imaging fields at the periphery of a vehicle 50. Then, the images acquired by the camera modules CA1 to CA4 are synthesized into a single overhead image of the periphery of the vehicle 50, and continuously-generated overhead images are, as a video picture, displayed on a display device placed at the periphery of a driver's seat.
In the case of synthesizing images acquired by the plurality of camera modules CA1 to CA4 into a single synthesized image, it is necessary to synchronize the plurality of images to be synthesized. Typically, image signals indicating images output from the individual camera modules CA1 to CA4 in a non-synchronized state are temporarily stored in a buffer, and then, the images of the camera modules CA1 to CA4 with approximate phases of vertical synchronization signals Vsync input together with the image signals are selected and read from many image signals stored in the buffer. Subsequently, the selected images are synthesized (Patent Document 1). That is, the phase difference among the images is eliminated by a storage time in the buffer, and the images input from the camera modules CA1 to CA4 are synchronized with each other to generate the synthesized image.